Done Mock_SQL2

[sakshiasati17]

No description provided.

[super30admin]

1. Correctness:

   • For "customers-who-bought-all-products.sql", the solution correctly identifies customers who bought all products by comparing the count of distinct products each customer bought with the total count of products. This approach is correct.
   • For "product-sales-analysis-iii.sql", the solution correctly identifies the first year each product was sold and returns the corresponding sales data. The use of a CTE with MIN(year) is appropriate.

2. Time Complexity:

   • For the first query, the time complexity is O(n) for scanning the customer table and O(m) for the product count, where n is the number of customer records and m is the number of products.
   • For the second query, the time complexity is O(n) for scanning the Sales table to find the minimum year for each product, and O(n) for the join operation.

3. Space Complexity:

   • Both queries create temporary tables (subquery in the first, CTE in the second), resulting in O(n) space complexity where n is the number of records in the respective tables.

4. Code Quality:

   • The code is generally well-structured and readable.
   • In "customers-who-bought-all-products.sql", the subquery could be replaced with a HAVING clause for better readability: SELECT customer_id FROM Customer GROUP BY customer_id HAVING COUNT(DISTINCT product_key) = (SELECT COUNT(*) FROM Product).
   • In "product-sales-analysis-iii.sql", the CTE is well-used, but the column alias 'first_year' in quotes is unnecessary in MySQL (though it doesn't affect functionality).

5. Efficiency:

   • Both solutions are efficient for their respective problems.
   • No major optimizations are needed, but the suggested improvement for the first query would make it more concise.